如何利用java求1000以内的回文素数？

Question

答案必须是

11 101 131 151 181 191 313 353 373 383
727 757 787 797 919 929

Answer 1

public class Test {
	public static void main(String[] args) {
		 
        for (int i = 1; i <= 1000; i++) {
 
            if (!check(i)) {
                continue;
            }
 
            if (huiweishu(i)) {
                System.out.println(i);
            }
        }
    }
 
    private static boolean check(int num) {
 
        int sqrt = (int) Math.sqrt(num);
        for (int j = 2; j < sqrt + 1; j++) {
 
            if (num % j == 0) {
                return false;
            }
        }
        return true;
    }
 
    private static boolean huiweishu(int i) {
 
        int a;
        if (i < 99) {
            a = i / 10;
        } else {
            a = i / 100;
        }
        return a == i % 10;
    }
}